DUBAI, June 10 (Reuters) - Qatar's central bank plans to issue 4 billion riyals ($1.1 billion) worth of local currency government bonds next week, it said on Tuesday, including a new seven-year tranche to build a longer yield curve.

The debt, to be auctioned on Sunday, will include 2.1 billion riyals worth of three-year conventional bonds and 950 million riyals each of five- and seven-year tranches, the central bank said on its website ( www.qcb.gov.qa ).

Qatar launched quarterly government bond sales in March 2013 to expand the central bank's policy arsenal and help banks manage liquidity. Since then, it has usually issued 3 billion riyals worth of conventional bonds and 1 billion riyals of sukuk each quarter; maturities have been three and five years.

Qatari officials have said they want to develop a deeper and more active local riyal-denominated bond market; lengthening the curve with a seven-year tranche is part of this process.

In the previous bond sale in April, the central bank issued 4 billion riyals of solely Islamic bonds; this month's auction will only involve conventional bonds.

The central bank has also been offering a fixed amount of 4 billion riyals worth of Treasury bills in regular monthly sales.

(Reporting by Martin Dokoupil; Editing by Andrew Torchia)

((Martin.Dokoupil@thomsonreuters.com)(+971 4 362 5832)(Reuters Messaging: martin.dokoupil.thomsonreuters.com@reuters.net))

Keywords: QATAR CENBANK/BONDS